By Zach Koons Although he said the All-Star center was feeling better, the Sixers coach was hesitant to sound too optimistic. 76ers star center Joel Embiid is feeling “a lot better,” but the timeline of his possible return to the court still remains unclear, according to coach Doc Rivers. Speaking to reporters ahead of practice on Tuesday afternoon, Rivers shared that Embiid was feeling much better after suffering an orbital fracture and concussion in Game 6 against the Raptors last Thursday. However, he exercised caution in his response, not wanting to sound too optimistic about the big man’s…